1. Field of the Invention
The present invention relates to a riveting apparatus, and in particular to a riveting apparatus having automatic feeding and automatic withdrawal of a workpiece.
2. Related Art
In numerous fields of manufacturing, riveting is widely used to combine parts. Most contemporary riveting processes are merely semi-automatic. That is, a workpiece is placed on a riveting apparatus. The workpiece is manually pushed to a riveting position. After completion of riveting, the workpiece is manually withdrawn from the apparatus. This process is not only unduly slow, but also prone to cause accidental injury to an operator""s hands and arms.
In order to increase productivity, fully automatic riveting apparatuses have been developed. Such apparatuses can perform feeding and withdrawal automatically. However, such apparatuses typically have a complicated structure and occupy a large space. Moreover, the apparatus is relatively expensive and consumes much energy, thereby inflating production costs.
Thus, a riveting apparatus which overcomes the abovementioned problems is desired.
Accordingly, an object of the present invention is to provide a riveting apparatus which can complete automatic feeding and automatic withdrawal readily and securely.
Another object of the present invention is to provide a riveting apparatus which has a simple structure.
A further object of the present invention is to provide a riveting apparatus which prevents operators from being accidentally injured.
To achieve the above-mentioned objects, an automatic riveting apparatus comprises a base, a feeding device and a riveting device. The base has a U-shaped support frame. A pair of photoelectric relays extends upwardly from the base. The feeding device comprises two parallel sliding rails, a lower die plate for supporting a workpiece, and a feed cylinder driving the lower die plate to slide along the rails. The riveting device has an upper cylinder and a riveting head. In operation, the feed cylinder is started up to drive the lower die plate together with the workpiece to a riveting position. The lower die plate touches a photoelectric contact point to actuate the upper cylinder. A piston rod of the upper cylinder drives the riveting head downwardly to rivet the workpiece. Then, the piston rod moves back up, and the lower die plate returns to its original position.